Field of Application
The present invention relates to the field of pressure sensor devices, particularly miniaturized electro-mechanical sensor devices, for use to measure pressures over a wide range (from overpressures but with the exception of high vacuum conditions), for example in machines, plants or instruments for measurements and analyses.
Background
Several electro-mechanical systems and devices for measurements of pressure are known.
A first category of devices comprises devices of the Pirani or thermo-cross type or devices of the MacLeod type, which are however considered as “low-end” devices, in terms of performance and measurement precision. Therefore, these devices cannot be used for many applications that require high precision and wider measurement ranges.
A second category of devices comprises diaphragm capacitive pressure sensors, which are considered “high-end” devices, in terms of performance and measurement precision. However, a first drawback of these capacitive pressure sensors is the range of measurable pressures, that is rather narrow for a given device. Therefore, in order to measure a pressure over a wide range of pressures, multiple pressure sensors have to be used in parallel: for example at least three capacitive pressure sensors in parallel are typically required for measurements over a pressures range between 10−4 mbar and 103 mbar, and no commercial instruments capable to measure pressures ranging from 10−4 mbar to 104 mbar are known
Moreover, in order to work efficiently in a real operating environment, the individual pressure measurement devices must include not only the pressure sensor itself, but also further components (for example, processing modules, interface modules, either wired or wireless, towards higher-level controllers, etc.). Thus, each of these devices becomes a “system”, even though of small dimensions. Disadvantageously, this reduces the reliability and increases the complexity of the devices, also increasing design and maintenance costs.
It should be further noted that a field of application, having a great and growing importance, is related to the use of pressure measurement systems/devices inside production machines or plants or manufacturing environments or analysis and measurement instruments, where it may be necessary to measure the pressure with a high precision, in many different points, over wide ranges, in often unfavorable environmental conditions, resulting in critical, or even extreme, operating conditions for the devices.
In this field of application, the need arises to have devices as compact, simple and miniaturized as possible, while maintaining high performance in terms of precision and reliability, and also significantly reducing the production and management costs thereof.
The known cited devices, both the “low-end” ones and the “high-end” ones, do not comply to this need in a satisfactory way.
In addition to the above, with reference to the properties of precision and reliability, calibration procedures, before use, and diagnostics procedures, during use, with possible re-adjustment or re-calibration, are more and more important.
Regarding this, the existing solutions do not offer a solution, or, at the most, they allow performing remote control procedures, by means of high level system controllers, which manage, for example, a plurality of devices in a plant. These control procedures may be complex and costly, in terms of time and resources needed.
More specifically, when compared with the requirements of the above-mentioned applications, the known sensor devices may have several drawbacks, among which: the non-perfect repeatability of pressure measurements, for example during pressure cycles of an industrial process; the existence of severe limitations of use in applications providing the exposure to corrosive gases environments; the difficulty of use in environments having abundant soot and particulate; the need to extract the device, from the system where it works, for calibration or re-calibration or cleaning, every time a new process cycle starts; finally, the need for a complex and cumbersome management and measurement system to obtain a microscopic measurement signal using macroscopic measurement and management instruments of the device.
Therefore, the further need of having pressure measurement devices as “self-contained” as possible, with respect to calibration and diagnostics, is much felt. Again, the known devices cited above do not offer suitable fulfillments to this need.
It should also be observed that the needs for miniaturization and self-sufficiency, even if they are both desired, may put conflicting design requirements which are very difficult to fulfill altogether.
In light of the above, the object of the present invention is to devise and provide a miniaturized electro-mechanical device for pressure measurements over a wide range (and a related measurement method), which results to be improved such as to fulfill the above-mentioned needs, and to be able to at least partially overcome the drawbacks described above with reference to the prior art.